Vehicle weight responsive means



Oct. 10, 1961 H. E. DYCHE, JR 3,004,152

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HIS ATTORNEY United States Patent 3,004,152 VEHICLE WEIGHT RESPONSIVE MEANS Howard E. Dyche, Jr., Wilkinsburg, Pa., assignor t Westinghouse Air Brake Company, Wilmer-ding, Pa., a corporation of Pennsylvania Filed Dec. 9, 1955, Ser. No. 552,152 4 Claims. (Cl. 246-451) My invention relates to vehicle weight responsive means, and particularly to means mounted in a slot formed in the web of a railway rail and responsive to the deflection of the portion of the rail above the slot as car wheels pass over the slot.

In certain forms of weight measuring devices previously used, deflection of the entire rail between two support points is measured and translated into weight readings. This arrangement had the disadvantage that it requires Very rigid rail supports and rigid rail anchoring means. Other types of weight measuring devices which have been used require entire rail sections to be supported on scales or'a portion of the rail head to be cut away to provide clearance for a weight responsive lever. The supporting of an entire rail section on scales requires an installation which is expensive to make and maintain, and the cutting away of a portion of the head of the rail is objectionable due to the resulting break in the wheel rolling surface.

It is therefore an object of my invention to provide a novel weight measuring device of the type described capable of operation over widely varying temperature conditions.

Another object of my invention is to provide a novel weight measuring device of the type described capable of low installation cost. I

Another object of my invention is to provide a novel circuit controller that is capable of operation within the slot of a rail and sufficiently sensitive to provide intelligi-ble readings in response to small deflections of the portion of the rail above the slot.

Another object of my invention is to provide a novel circuit controller capable of being entirely contained within the overall width of the rail within which it is installed.

Other objects, purposes and characteristic features of my invention will be in part obvious from the accompanying drawings and in part pointed out as the description of.

the invention progresses.

In the following description the slotted member is referred to as a rail having an upper portion, an intermediate portion, and a lower portion, since this is the preferred embodiment. However, it is to be understood that the slotted member may be any beam carrying a variable load.

In practicing my invention I provide a circuit controlling device located within an opening formed in the intermediate portion of a railroad rail or other load carrying device. The circuit controlling device is positioned to be responsive to the deflection of the upper portion of the rail into the opening in response to a passing load. The circuit controlling device comprises a plurality of carbon resistance devices arranged to be controlled by the deflection of the upper portion to vary their resistances. The carbon devices are connected into a Wheatstone bridge circuit arrangement for providing maximum response to any deflection. The response may be used for any desired purpose such, for example, as to provide weight information for use in automatically controlling the braking action of a car in accordancewith'the weight of the car.

The provision of a circuit controlling device which can be mounted in the opening in a rail intermediate portion, as indicated, eliminates the need for special and expensive rail supports. The type of circuit controlling device disclosed is also capable of being operated through small upper portion deflections.

In describing my invention in detail, reference will be made to the accompanying drawings in which corresponding parts are generally identified by con-responding reference characters and in which:

FIG. 1 is an elevational view of my novel weight responsive device mounted in place in a rail opening in accordance with my invention.

FIG. 2 is a top view of my novel circuit controlling device as it would appear when removed from the opening formed in the intermediate portion of the rail.

FIG. 3 is a sectional view taken along the line III--III of FIG. 2 to better show the operating structure of my circuit controlling device.

used with the embodiment of my invention shown in FIG. 5.

FIG. 7 is a response curve showing a typical action of the detection circuit of FIG. 5. t

In classification yards the need has arisen for quick acting weight responsive circuit controlling devices that will weigh a single wheel passing over a desired location without the other wheels affecting the response. The need has arisen due to the use of automatic retarders in which it is necessary for initial retarder shoe pressure to be established according to the weight per wheel of a passing vehicle. Hence, a lightly loaded vehicle would receive a low initial shoe pressurewhile a heavy vehicle would receive a high initial shoe pressure.

Referring to FIGS. 1, 2, 3 and 4 of the drawings showing one embodiment of my invention, the reference character 1 designates a rail or beam having an upper portion 2,

- an intermediate portion 3 and a lower portion 4. Formed within the intermediate portion 3 of the rail '1 is an elongated opening 5 extending transversely from side to side through the intermediate portion. The opening 5 is sufficiently elongated to allow deflection of the upper portion 2 into the opening 5 in response to the passage ofa typical wheel 5a. To prevent the upper portion 2 from exceeding its elastic limit upon passage of a vehicle wheel carrying a large load, the stop members 6 are secured in place against the bottom surface of the elongated opening 5 and spaced from the lower surface of the upper portion 2. The stop members 6 are spaced from the upper portion 2 a suflicient distance to allow an intelligible amount of deflection of the upper portion, while at the same time limiting the deflection to a value well within the elastic lirnitof the rail. The stop members 6 are provided with downwardly extending lugs 7 which are off-set to one side of the main port-ion of the stop members 6 to allow the lugs to pass downwardly along the side of the intermediate portion 3 of the rail 1. A bolt 8 is then passed through an openare a plurality of insulating walls 13 forming four spaced apart rectangular cavities or recesses 14. The cavities 14 have positioned therein a plurality of carbon discs 15 forming carbon piles CPI, P2, 0P3 and CP4. L0- cated above and below each of the carbon piles are terminal strips I8 for making electrical connections. Positioned above each of the top terminal strips 18 on each carbon pile is an insulating pressure block 19 bringing the level of each of the carbon piles above the insulating walls 13 forming the cavities I4.

Inserted into the space between the carbon. piles CPI and CP4 is a generally U-shaped pressure bridge member 20 provided with horizontal extensions 21 for engaging the insulated pressure blocks 19 of the carbon piles CPI and CP4. The pressure bridge 20 is secured in place by an adjustable screw 22 passing through an opening 23 in the pressure bridge member 20 and threaded into an opening 24 in the base member of the circuit controller 9. Surrounding the screw 22 and positioned between the head of the screw and the pressure bridge member 20 is a coil spring 25 used to apply an initial pressure to the carbon piles CPI and CP4. Spanning between and secured to each of the horizontal extensions 21, of the pressure bridge member 20, is a bridge actuator 26 provided with an upstanding rail contactor portion 27. The bridge actuator 26 is secured to the horizontal extensions 21 by a pair of screws 28.

Parallel and in close proximity to the carbon piles CPI and CP4 are the carbon piles CPZ and CPS. The carbon piles CPZ and CP3 are arranged and secured in place in the same manner as the carbon piles CPI and CP4 with the exception that the carbon piles CPZ and CP3 do not have a bridge actuator located between their cooperating U-shaped pressure bridge and the upper portion 2 of the rail 1. The U-shaped bridge for the carbon piles CPZ and CP3 is generally designated as 2P and is secured in place by an adjustable screw and spring assembly 30.

The carbon piles CPI, CPZ, CP3 and CP4 are connected to form the legs of a Wheatstone bridge by the conductors 32, 33, 34 and 35 with the carbon piles CPI and CP4 forming opposite legs of the bridge. Supplying the Wheatstone bridge With power is a battery 36 connected to the conductors 32 and 34 by the conductors 37 and 38 respectively (see FIG. 4). The detector circuit conductors 39 and 40 are connected to the conductors 33 and 35 respectively, completing the Wheatstone bridge arrangement utilizing the carbon pile legs CPI, CP2, 0P3 and CP4.

The conductors 37, 38, 39 and 40 are secured within a housing forming an electrical cable 41.

The detector circuit comprises three relays L,M and H each having two windings and a normally closed back contact. The first winding of each relay is connected in parallel with the first winding of each of the other relays and to the conductors 39 and 40. The second winding of the relays L, M and H are connected through the adjustable resistors 42, 43 and 44, respectively, to a source of power or battery 45 which provides an adjustable bias on each relay. With this arrangement the relays L, M and H can be biased to attract their movable contacts on different current levels as will occur in the Wheatstone bridge detector circuit upon different amounts of rail deflection. For example, the relay I may be biased to attract its contacts with a verysmall amount of rail deflection causing small amount of unbalance of the Wheatstone bridge, while the relay M may be biased a smaller amount requiring a greater amount of rail deflection and bridge unbalance, and the relay H may be biased an amount requiring a large amount of rail deflection and bridge unbalance.

Operation of the structure recited and shown in FIGS. 1 through 4 will now be explained. With no vehicle passing, it can be seen that the spring andsecuring structure of the U-shaped bridge members 20 and 29 cause the U-shaped bridge members to apply an initial pressure to the carbon piles CPI, 0P2, CP3 and 0P4. This means that each of the carbon piles will have an initial resistance to the flow of current from the battery 36. The resistances are desirably equal, establishing a balanced bridge. As the wheel of-a train rolling along the surface oi the rail I approaches and passes over the opening 5, causing the railhead to deflect, it can be seen that the carbon piles CPI and 0P4 have an additional pressure applied. This additional pressure causes the resistance of the carbon piles CPI and CP4 to decrease. Since the carbon piles CPI and 0P4 are in opposing legs of the Wheatstone bridge, an unbalance of the Wheatstone bridge will occur causing a current to flow in the conductors 39 and 40. With the conductors 3? and 40 connected to the first winding of each of the relays L. M and H, the current due to the Wheatstone bridge unbalance, will flow through each relay first winding. If the loading of the typical Wheel 5a is that of a light vehicle, the pressure applied to the carbon piles CPI and CP l will be small and the amount of unbalance of the Wheatstone bridge will also be small. Under these conditions the relay L will attract its contacts since it is the only relay receiving sufiicient bias from its second winding current flow to produce sufiicient flux to cause its movable contact to be attracted, opening its back contact. If the wheel 5a is that of a vehicle carrying a medium load, a greater rail upper portion deflection pressure will be applied to the carbon piles CPI and'CP i causing a still lower carbon pile CPI and CP4 resistance. This causes a greater unbalance of the Wheatstone bridge and a greater flow of current through the first winding of each relay. Under this condition the combined bridge current and bias current produces a fiux in the relays L and M causing these relays to attract their movable contacts while the relay H movable contact remains dropped away. If the maximum load is carried by the wheel 5a, the deflection of the upper portion 2 of the rail I is increased to the maximum and the resistance of the carbon piles CPI and CP4 is reduced to a minimum. The Wheatstone bridge will then be under its greatest unbalance and current flow condition. The combined bridge current and bias current will thus cause suthcient relay flux in all of the relays to cause them to attract their movable contacts. The two carbon piles CPZ and CP3 comprising the legs of the Wheatstone bridge which are not affected by the rail upper portion loading are used for temperature compensation purposes. For example, a change in temperature which would affect the resistances of the carbon piles CPI and CP4 would also make a corresponding change in the resistances of the carbon piles CP2 and CP3 since they are located adjacent to the resistances CPI and 0P4. The change in temperature would therefore not affect the balance of the bridge.

The second embodiment of my invention, shown in FIGS. 5, 6 and 7 of the drawings, is a circuit controller comprising an insulated base 5% provided with a downwardly extendinglip 51 having openings 52 for receiving circuit controller securing bolts, such as the bolts 12 shown in FIG. 1. The base 50 is provided with upstanding insulating walls 53 forming a pair of spaced apart recesses 54 for receiving two pairs of carbon piles forming two stacks of carbon piles with a stack positioned within each recess 54. Spanning the space between the recesses 54 formed by the upstanding walls 53 is a support bridge member 55. The support bridge member 55 is provided with a pivotedsupport 56 for supponting the lever arm 57 on a pivot 58. The lever arm 5'7 spans the distance between the two stacks of carbon piles and is provided with carbon pile cooperating pressure points 59 and 60 which are positioned over the center of the carbon pile stacks located Within the recesses 54. Positioned on the lever arm 57 facing the opposite direction from the pressure points 59 and 60 is a lever arm actuating contaotor 61 which cooperates with the upper portion 2 of the rail 1 in the manner similar to the rail contactor portion 27 shown in FIG. 1. The lever arm 57 is extended outwardly be yond one of the carbon pile stacks and is provided with a downwardly oflset portion 62 having an opening '63 for receiving an adjustable screw 64 and its cooperating lock nut 65. The head of the adjustable screw 64is provided with the coil spring seat for receiving a leverarm 57 biasing coil spring 66. The spring 66 is centered and held in position on the screw 64 by the spring seat and is extended to the base 50 and retained in place on the base 50 by a dimple 67. Secured to and extending upwardly from the base 50 is a travel limiting arm 6-8 for the lever arm '57. The travel limiting arm 68 extends beyond the end of the oflset lever arm extension 62 and is provided with a horizontally extending portion 69 overlapping the oflset extension 62; Threaded through an opening in the horizontally extending portion 69 is lever arm 57 travel limiting adjusting screw 70 having a lock nut 71 for retaining the screw in position.

Each of the carbon piles located in the recesses 54 formed by the walls 53 comprise a pair of terminal strips 18 and a plurality of carbon discs 15. The carbon piles of each stack are electrically separated by an insulating pressure block 19 and each pair of carbon piles (or each stack of carbon piles) is provided with an upper'insulating pressure block 19. For this reason the two pairs of carbon piles located within the recesses 54 are electrically independent members.

With the arrangement of the circuit controller described above it can be seen that the carbon piles CPI, CPZ, CP3 and CP4 located within the recesses 54 can be connected intoa Wheatstone bridge circuit so that the two carbon piles located within a single recess would be connected into opposite Wheatstone bridge legs. For example, the carbon piles CPI and CP4 would be one set of opposing legs while the carbon piles CP2 and CP3 would be the other opposing legs. With the spring 66 forcing the lever arm 57 into one of its extreme positions, as shown in FIG. 5, the carbon piles CP2 and CP3 are placed under an initial maximurn pressure while the carbon piles CPI and CP4 are under a minimum initial pressure. With the carbon piles CP2- and CP3 placed under a' maximum initial pressure and the carbon piles CPI and CP4 under minimum initial pressure it can be seen that the Wheatstone bridge comprising the four carbon piles would :be under an initial unbalanced condition.

A detection circuit for the Wheatstone bridge is connected to the common points 77 and 78 located between the carbon piles CPI, CPZ and CPS, CP4, respectively, over the conductors 79 and 80. The detection circuit comprises three double winding polar stick relays L, M andH whose contacts are movable between two extreme positions and which are provided with their first windings connected in parallel across the conductors 79 and 80. The second winding-of each of the relays L, M and H is provided with biasing network comprising a source of power or battery 85 that is center tappedas at 84 and connected to one of the two terminals of eachfrelay second winding. Connected in parallel across the battery are three resistance members 81, 82 and 83' each provided with a variable resistance tap. The variable resistance tap associated with the resistance 81 is connected to the remaining second winding terminal of the relay L, the variable resistance tap of the resistance 82 is connected to the remaining second winding terminal of the relay M, and the variable resistance tap of the resistance 83 is connected to the remaining second winding terminal of the relay H. As the taps'on the variable resistances 81, 82 and 83 are moved from one extreme position to the other the flow of current in the relaysecond windings will be from ainaximum in one direction decreasing to zero and increasing to a maximum in the other direction. This biasing arrangement is necessary since the relays L, M and Hare polarized relays and it may be found necessary to bias the relays with currents of difi'erent directions of flow as will be explained hereinafter.

The curve shown in FIG. 7 is a typical curve showing the relationship of rail deflection to current necessary for actuating the relays L, M and H in the circuit of FIG. 6. The line A and the curve of FIG. 7 denote the response line of the Wheatstone bridge arrangement in which under zero deflection of the rail a maximum current flows in one direction, since this is normally an unbalanced bridge. The line B, in the curve of FIG. 7, is a line representing the combined currents of the first and second windings of the relay L, the line C is a line representing the combined currents of the first and second windings of the relay M, and the line D is a line representing the combined currents for the first and second windings of the relay H. Since the relays are polar stick relays it is necessary to show the typical combined current response curve under which conditions the relay would move its contacts from one position to another. For example, in FIG. 7' the line B represents the combined currents necessary to move any of the relay contacts into one of their positions. The line F represents the combined currents necessary to move the relay contacts from the one position to the other position. Once the relationship of the amount of deflection to relay contact movement has been selected by adjustment of the second winding bias current level, the bias normally remains constant. It therefore can be seen that the bias on any relay at any amount of deflection can be represented by the vertical distance between the line A and any of the combined current lines B, C and D. For the selected deflections shown in the drawings the bias current is distinguished by the heavy lined positions of L1, L2, M1, M2, H1 and H2. For example, the current necessary to move the relay contact of the relay L from its initial position to the actuated condition due to de flecton of the rail is represented by the line L1 of the curve of FIG. 7. The line L1 is made up of two basic currents, the first is the current in the first winding due to the Wheatstone bridge detector current and is indicated by the portion of the line L1 between the curve A and the zero (or deflection) line and designated as the first winding I. The second current is found in the second winding and is represented by the heavy portion of the line L1 (designated as second winding I), which is the portion of the line L1 located between the response line A of the Wheatstone bridge and the combined currents I for the relay L, represented by the line B. This is a bias current thus is of a constant value regardless of rail deflection.

A tracing of the current effects on the relay L from zero deflection to a deflection at which the contact of the relay would move to its opposite position is as follows: With zero deflection the line A shows a maximum flow of current in a negative direction -at the point where it meets the vertical axis of the curve. With a positive initial bi-as applied to the second winding of the relay L, as represented by the distance between the line A and the line B, it can be seen that the only variable is the current in the relay first winding which changes due to deflection of the rail. As the rail deflection increases and the relay first winding current becomes less and less negative the resultant finst and second winding currents follow a line (line B) parallel to the Wheatstone bridge response line A. "The combined currents continue to follow the line B until it reaches and'passes zero value and increases to the point G. At this time the combined currents inthe first and second windings produce suflicient relay energy to move the relay contact to its one position. This action is indicated by the intersection of the combined relay current line B and the relay combined current response line B. If we assume that the deflection of the rail stops at this amount the relay L will be the only relay provided with suflicient combined currents to move its contact from its original to its one position. This can be seen by the fact that the lines C and D have not reached the relay response line E. If we now assume that the load is being removed from the rail and the rail deflection is returning from its deflected position back to zero deflection, it can be seen that the combined currents on the relay L will first fall below the relay actuating current at point G which was necessary to move the relay contact upon rail deflection. Since, however, it is necessary to have a current sum amounting to a reversal of current and of a value represented by the line F to return the relay L contact to its original (or other) position, the contact will hold in its actuated position. For example, if we follow the combined current line B back down as the deflection decreases we find that the relay L will not receive suflicient current to return its contact to the first (or other) position until it reaches the point K. At this time the relay combined current response line F crosses the combined current line B of the relay L.

A tracing of the combined current line for the relay M is similar with the previously traced current line of the relay L with the contact moving to one position at the resultant current line M1 and to the other position at the line M2, therefore will not be repeated. The current line for the relay H however is slightly different from the two previous relays, since we find that the current response line A of the Wheatstone bridge detector circuit crosses the combined current line F necessary to move the relay H contact to a new position before the deflection of the rail reaches the desired position selected for actuation of the relay H. It is therefore necessary to bias the relay H with a bias in a negative direction to bring the relay H current response line, indicated as D, down below the current line of the Wheatstone bridge detector circuit. This prevents the relay H from responding until its combined currents reach the level of the line B, as occurs at the point P on the line H1. Dividing the current response line Hit of the relay H into its components, it can be seen that the current of the relay first winding would be indicated by the distance between the line A and the deflection line axis of the curve. This current is in a positive direction as shown on the curve. The bias current found on the second winding of the relay H is indicated by the portion of the line H1 located between the line A (current of the Wheatstone detector circuit) and the line D (indicating the combined currents for the relay H). This current is in a negative (or the opposite) direction to the detector circuit current which gives a resultant current of the amount indicated between the deflection axis and the point P. Tracing the relay *action'back down the combinedcurrent line D shows that the return of the relay contact to its other'position occurs when the resultant current is as shown by the line H2.

Although the second winding of the relay H is shown biased by a current of opposite polarity to the bias on the relays L and M, it is to be understood that any one or all of the relays may be biased with either polarity as is necessary to get the relay'to respond on the desired amount or" rail deflection.

Although I have herein shown and described only two forms of the novel weight circuit controller embodying my invention, it is to be understood that various changes and modifications maybe made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a rail having upper, intermediate and lower portions and having an opening within the intermediate portion'which extends transversely from side to side through said intermediate portion and is sufiiciently elongated lengthwise of the rail and located sufliciently close to the upper portion to permit upper portion deflection into said opening to cause a narrowing thereof upon the application of a load on the upper portion above said opening, an upper portion deflection detector comprising four carbon piles, said carbon .piles changing their electrical resistance in response to pres sure changes, two of said piles insulatively mounted in a first stack and the other two of said piles insulatively mounted in a second stack spaced from said first stack, said two stacks being mounted within said slot, said carbon piles being electrically connected in series with one another to form the legs of a Wheatstone bridge, said piles in said first stack forming opposite legs of said bridge, a pressure lever pivoted adjacent said two stacks, one end of said lever bearing on said first stack and the other end of said lever bearing on'said second stack, biasing means for biasing said lever to apply a high initial pressure on the two carbon piles in said second stack and a low initial pressure on the two carbon piles in said first stack, said one end of said pivoted pressure level contacting said upper portion and being actuated by upper portion deflection for increasing the pressure on said first stack while concurrently decreasing the pressure on said second stack, a source of-power arranged to be connected between two alternate junctions of said series connected piles, and Wheatstone bridge detecting means connected across the other two junctions of said series connected carbon piles for detecting any change in said Wheatstone bridge resistances.

2. In combination with a rail having upper, intermediate and lower portions and having an opening formed within the intermediate portion which extends transversely from side to side through said intermediate portion and is sufliciently elongated lengthwise of the rail and located sufficiently close to the upper portion to permit upper portion deflection into said opening to cause a narrowing thereof upon the application of a load on the upper portion above said opening, an upper portion deflection detector comprising four carbon piles mounted in spaced relation within said opening, saidfour carbon piles changing their electrical resistance in response to pressure changes, said carbon piles being electrically connected inseries with one another to form the legs of a Wheatstone bridge, a pair of pressure members, biasing means for biasing one of said pressure members to apply an initial pressure on two of said carbon piles and the other pressure member to apply an initial pressure to the other two carbon piles,.an actuator member bearing on one of said pressure members and contacting said upper portion to be actuatedthereby for causing anincreasing pressure on two of said carbon piles whilesaid other pressure member maintains an initial or reference pressure on said other two carbon piles, a source of power arranged to be connected between two alternate junctions of said series connected piles, and Wheatstone bridge detecting means connectedacross the other of two junc tions of said series connected carbon piles for detecting any changes in the Wheatstone bridge resistances.

3. In combination with a railhaving upper, intermediate and lower portions and having an opening formed within the intermediate: portion which extends transversely from side to side through said.intermediate portion and is sufficiently elongated lengthwise of the rail and located sufliciently close to the upper portion to permit upper portion deflection into said opening to cause a narrowing thereof upon the application of a load on the upper portion above said opening, first and: second groups of electrically connected carbon pile resistance members arranged in theform of a Wheatstone bridge with the carbon piles in the first group forming opposite legs of said bridge and responsive to pressure changes by varying the electrical resistance .therethrough, means for'applying an initial pressure to all'of said resistance members, the resistancemembersin said second group being temperature compensatingmembers, a pressure member operatedby said upper portion to increase the pressure on the resistance members of said first group and thereby change-their resistance upon deflection of said upper portion, and electrical detector means for responding to changes in the resistance of the members of said first group.

4. In combination with a rail having upper, intermediate and lower portions and having an opening formed within the intermediate portion which extends transversely from side to side through said intermediate portion and is sufficiently elongated lengthwise of the rail and located sutficiently close to the upper portion to permit upper portion deflection into said opening to cause a narrowing thereof upon the application of a load on the upper portion above said opening, a variable electrical resistance device in said opening comprising a plurality of carbon piles, means for applying an initial pressure to said carbon piles, a pressure member cooperating with said upper portion for increasing the pressure upon upper portion deflection, groups of carbon piles being electrically connected into a Wheatstone bridge detector means for detecting the change in resistance of said first group of said carbon piles, said first group forming oppo- 20 10 site legs of said bridge, said Wheatstone bridge detector means including a plurality of relays biased to respond to different levels of carbon pile pressure change.

References Cited in the file of this patent UNITED STATES PATENTS 756,208 Bugler Apr. 5, 1904 1,889,663 Ilyus Nov. 29, 1932 1,952,171 Jones Mar. 27, 1934 2,183,078 Kemler Dec; 12, 1939 2,414,161 Moore Jan. 14, 1947 2,779,583 Bone Ian. 29, 1957 1 2,866,137 Blosser Dec. 23, 1958 FOREIGN PATENTS 905,461 France Dec. 5, 1945 829,805 Germany Ian. 28, 1952 457,295 Great Britain Nov. 25, 1936 698,793 Great Britain Oct. 21, 1953 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No S OOQ 152 Octoberl0 1961 Howard E. Dyche Jr.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7 line 69 after "opening" insert formed column 8 line 18 for "level read lever column 9 line l3 for ,a plurality" read groups ---3 lines l5 and 16 for "a pressure member cooperating with said upper portion for increasing the pressure" read means cooperating with said upper portion for transmitting an increase in pressure to Ya first one of said groups of carbon piles line 1'2 before I "groups" insert said '---3 same column 9 line 19 after f'first} insert one line 20 for, "group of said carbon" read of said groups of carbon Signed and sealed this 3rd day of April 1962 (SEAL) Attest:

ERNEST W. SWIDER DAVID L, LADD Attesting Officer Commissioner of Patents UNITED sTATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3 004 152 October 10 1961 Howard E. Dyche Jr.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. j

Column 7 line 69 after "opening" insert formed column 8, line l8 for "l-evel read lever column 9, line l3) for a plurality"v read groups lines 15 andlo for "a pressure member cooperating with said upper portion for increasing the pressure" read means cooperating with said upper portion for transmitting an increase in pressure to a first one of said groups of carbon piles ..g line 17 before L "groups" insert said 5 same column 9 line 19 after Jfirst'; insert one line 2O for group of said carbon" read g of said groups of carbon f Signed and sealed this 3rd day of April 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID. Lo LADD Attesting Officer Commissioner of Patents 

